Process of manufacturing cane-sugar.



N. M. THOMAS & C. G. PETREE. PROCESS OF MANUFACTURING CANE-SUGAR.

APPLICATION FILED JAN. I4. I918.

Patented May 21, 1918.

NEEEMIAH-MORTIMER THOMASQ'OF PYMBLE, NEAR SYDNEY,.1\TEW SOUTH WALEStANDI r orrcn.

on'rnnnn'r enonen rn'rnnn, or nt'mnABE'R-G, QUEENSLAND, A'U'STRALIA;

. necneee.

. Specification of Letters Patent.

PROCESS OF MANUFACTURING CANESUGAR.

Application filed January 14, 1918. Serial No. 211,703. i

cane is defecated by the addition of lime and the applicat-ion of heat.In this treatment a heavy precipitate of scum and mud, hereinaftercalled mind, is produced, and collected by settling-and decantation.lfhe mud is pumped into filter presses and the filtrate is returned tothe raw juice oris added to clarified juice drawn from the settlingyessels. lln-some' instances the whole of the juice after defecation ispassed through filter presses. b

Extraction .of sugar chargeddiquids from defecation mud by filterpressing or by treating it in centrifugal machines is subject to thedisadvantage that costly apparatus involving considerable labor costforits operation is necessary. g It has been proposed to extract thesugar charged liquid from the mud returning themud. to the millingcircuit at a point therein subsequent to the initial shreddingor,crushing, with the/object that'the sugar charged liquid it containswill be expressed by subsequent crushing'and its solid elements retainedin. the megass. his not ultimately profitable to return to the millingcircuit the defecation mud produced from rich juice or from mixed richand thin'juices obtained respectively in the early stage or stages ofthe crushing, because the liquid contained in the mud so produced isricher in sugar than is the liquid content of the macerated megass whichenters the rolls at the stage of crushing following next aftertheapplication of the mud to the megass.

-- A satisfactory efliciency of extraction of a sugar from the cane isattainable only when w the megass in process of crushing is subjected toprogressive ,maceration and for-this purposethe sugar content in theexpressible liquids must progressively diminish. The

a. usual method when more than two stages of crushing areemployed is toreturn thethin 'juicefrom the final. stage or sta es of the crushmg tothe megass after it eaves the Patented may at; ota.

early stage or stages of the crushing and to apply maceration water tothe megass prior to the final stage or stages.

Our invention has for its object to provide a means whereby the sugarcharged liquid may be extracted from the defecation mud by distributingsuch mud on the meg-ass in the milling circuit. without the addition ofplant which is costly to operate, and without the disadvantage ofrequiring increase in the volume of maceratlon water-otherwise necessaryfor reducing the residual sugar in the final megass to a practicalminimum, and without detriment to the -eficiency of the extraction ofsugar from the cane.

Our intention consists in distributing upon the 'megass in the millingcircuit a specially prepared defecation mud. This special preparation ofthe mud is effected by mixing mud produced from defecation of rich juicewith raw'thin juice obtained in a later stage or stages ofmultiplecrushing and submitting the mixture to defecation and settlingthence withoutincreasing the quantity of maceration water otherwisenecessary. obtaining a mud the liquid element of which is less rich insugar: than is the liquid content of the macerated mega whlch enters therolls at the stage of crushing following next after the saiddistribution of such mud 011 the inegass.

We may proceed in either of two ways,

, whichare identical in principle and object.

In the first case we add the mud produced from defecation of the richjuic (5. e., the natural juice obtained in the first stage or stages ofthe crushing) to the raw thin juice obtained in a later stage or stagesof crushing, and we mix the clarified juice from the thin juicedefecation with the rich juice, before the latter is defecated, takingthe clarified juice from the defecation of the mixture of rich juice andclarified thin juice direct to the evaporating plant. After the processis established in operation this mud obtained from the defecation ofso-called rich juice isin. fact mud obtained from the defecation of amixture of raw rich u ce and the previously defecated clarified thinuice. In the the clarified thin juice with the raw ric juicefand insteadthereof carry the clarified second case we'may omit the step of mixinthin juice direct I to the evaporating plant separately or'inconjunction with the clarified rich juice. In either case the sugarcontent in'the liquid element of the mud isreduced below the sugarcontent in the liquid contained in the macerated first megass enteringthe second mill, so that it can be safely introduced into the millingcircuit after the first crushing. I

The process will suffer appropriate adaptation in each case, havingregard to the mill plant in which it is-installed, accordingto currentprinc ples of sugar mlll operation. In a three mill crushing plant, forinstance, the specially prepared defecation mud and't-he rawjuice fromthe third mill, separately or admixed, would be applied to i the megassafter it'leavesthe first mill, and i the megass "after leaving thesecond mill- ,would be macerated with Water. Our first method isdiagrammatically illustrated for a threemill crushing plant in Figure 1of theaccompanying drawing; and

V our modified method-for a similar plant is tling vessel H. Theclarified juice from the settling vessel H passes to the evaporatingplant by the pipe line J and the mud'pa'ssesx ,by the pipe lineor-launder K to the tank goes by the pipe line Q to the ta whichreceives the screened thin juice from the mill B, via the screen M. Themud and the thin juice are limed and'transferred. by the pump Nfromtheta-nk L to the heater 0 and thence to the settling vessel Pf Theclarified juice from-the settlin vessel P .E, where it mixes with therich juice and the mixture is defecated. iT-he mud from 'the settlingvessel P goes by the pipe line or launder R, to the megass between themill A and the mill B. Maceration water is applied to' the megassbetween the mill B and the mill 0, and

, the thin juice from the mill .0 may be applied either with the mudfromithe settling vessel P, or separately, to the megass. .In Fig. 2 theonly difference from the process above described is .that the clarifiedjuice from the settling vessel P goes .dlrect to the evaporating plantby the pipe line S, instead of' being brought to the tank E.

Obviously the introduction into the milling circuit of mud containing inits liquid element a higher percentage of sugar than is carried by theliquid in the macerated me-.

gass entering the rolls at the stage of crushing following suchintroduction .of mud militates against the successful operation of themilling process, and either increases the quantity of the sugar lost inthe final megass or renders necessary the addition of an otherwiseunnecessary. quantity of water to reduce to a reasonable margin of lossthe quantity of sugar which remains in the final megass, therebyentailing additional cost for evaporating the su'peradded water.

It is not practicable to add the defecation mud to the shredded canebefolcthe first crushing, as the shredded cane is at that stage heavilycharged with juice and is not capable of absorbing any substantialquantity of additional liquid or of effectively retaining the solidelements of the mud.

What we claim as our invention and desire to secure by Letters Patent isI 1. In a process for extracting sugar cane juice by successivelycrushing and macerating sugar cane, defecating the extracted products,and returning the defecation mud to the milling circuit, producing aspecially prepared defecation mud for the said purpose by first mixingthin juice with mud obtained from defecation of richer juice anddefecating the mixture whereby a mud is produced the liquid element ofwhich is lower in sugar content than is the liquid element in themacerated megass with which such mud is incorporated and crushed. 2. Ina process for extracting sugar cane juice. by successively crushing andmacerating sugar. cane, defecating the extracted substances andreturning the defecation mud to themilling circuit, reducing the sugarcontent of the liquid element in the defecation mud below thesugarcontent of the liquid element in the macerated megass which entersthe rolls at the stage of crushing'fo lowingnext after the point in themilljuice by successively crushing and macerating sugar cane, whereindefecation mud is returned to the milling circuit for the extraction ofsugar charged liquid therefrom and for the retention of the solidelements of said mud with the megass, mixing mud obtained fromdefecation of relatively rich juice or juices extracted in the firststage V ing-circuit at which said mud is returned to or stages of'thecrushing, with raw thin juice extracted in the later stage or stages ofthe crushing and defecating this mixture of mud and raw thin juice-toprocure thereby a final min the liquid element of which is lower insugar content than is the liquid element of the macerated megass whichenters the rolls at the stage of crushing following next after the pointin the milling circuit at which said mud'is returned to'said circuit. v

sists in submitting the cane 'to a succession of crushings withintermediate maceration of the megass, defecating and settling the thinjuice obtained in the late stage orstages of thecrushing, admixing theclarified juice from said thin juice with. rich juice obtained in theearly stage or stages of the crushin defecating such mixed juiceseparately rom said thin juice, admixing the defecation mud from thesaid mixed juice which is rich in sugar content with said thin juiceprior to defecation of said thin juice and distributing the mud which isobtained from the defecation of such mixture of mud and thin juice uponthe megass at a point in the milling circuit where the liquid element ofsaid mud is lower in sugar content megass which enters the rolls at thestage' than is the liquid element of the macerated of crushin followingnext after the point in the-milling circuit at which said mud isdistributed on the megass.

5.111 a process for extracting'sugar canejuice by successively crushingand macerat-.

mg sugar cane, and defecating the extracted stage of crushin productsand returning the defecation mud to the milling circuit, reducing thesugar content of the liquid element of the mud prior to returning it tothe milling circuit below the sugar content of the liquid element of themegass which enters the rolls at the point in the mil 'ng circuit atwhich said mud is returned by reducing the sugar confollowing next afterthe i tent of'the raw rich juice by admixing clari- -fied thin juicetherewith,.thus reducin the sugar content of the defecation mu ob-.tained from said rich juice and admixing ate'd mud and raw .thinjuicefor the production of said clarified thin juice and of a stillfurther attenuated mud for returns ing to the milling circuit, 7

6. The herein described improvement in the extraction of sugar canejuice, which consists in crushing the cane in a plurality ofstages withintermediate maceration of the megass, defecating the rich juiceobtained in the early stage or stages of the crushing, passing theclarified rich juice to the factory and mixing the rich mud therefromwiti raw thin juice obtained in the late stage or stages of thecrushing, defecating the mixture of rich mud and raw thin juice, passingthe clarified thinjuice to the evaporating plant and distributing themud therefrom upon the megass at a point in the milling circuit wherethe liquid element of the mud is less rich in sugar than is the liquidcontent of the macerated megass which enters the rolls at the stage ofcrushing following next after the said distribution of mud upon themegass. 7 In'testimony whereof we have signed our names to thisspecification in the'presence of two subscribing witnesses.

. NEHEMIAH MORTIMER THUMAS.

CUTHBERT GEORGE PETBEE.

Witnesses:

W. J. DAVIS, HEATHER PETER.

